Music, text, images and other types of copyrightable subject matter are now routinely produced in digital or electronic form for distribution in physical form (e.g. compact disks, digital video disks) or electronically (e.g. via file transfer between networked computers). Electronic distribution makes it possible to distribute products cost-effectively by eliminating packaging, transportation and other costs associated with getting physical goods to the consumer. Because hard drive space is significantly cheaper than retail shelf space, distributors can offer more product choices and can make their products available at more digital locations, i.e. web sites.
Computer networking technology has brought new challenges to the policing of copyright interests in materials distributed in or convertible to digital form. Electronic copies are effortlessly created and/or distributed from one computer to another or many others via local networks (LANs), wide area networks (WANs) and the Internet.
Unauthorized copying of digital materials is of particular concern in the music industry, though efforts have been made to prevent it. Technology has been employed to secure audio materials and receive payment by requiring consumers to purchase from a centralized point in an effort to control access to the files. Access to the files may be further restricted by requiring that the files be played on a proprietary player that has the ability to verify that payment for the file has been made. In this model, consumers can only access the subset of audio that is made available at the hosting company's site, and files can only be played on the hosting company's player, which may not be the consumer's player of choice. Sony recently announced the introduction of a pocket-sized digital music player. The player receives small device-specific memory cards which carry digital files that are available for purchase and download over the internet.
U.S. Pat. No. 5,765,152 to Erickson (“Erickson '152”) describes a system and method for managing copyrighted electronic media. Erickson '152 describes the use of a registration system to make documents available over a computer network, and an authorization system for end-users to obtain desired level of permission to use and alter the document, and then to subsequently register the resulting derivative work. According to the Erickson '152 system, permissions are attached to the document file, and the user downloads or accesses the document file with the appropriate permissions attached to the document file. Thus, the permissions must co-exist with the documents. This is disadvantageous for a number of reasons. For example, if the user loses a document file, he/she also loses their permission to use the document. Further, Erickson's system contemplates distribution of documents through specific servers, i.e. the author does not have the option of posting the document from any server he/she chooses and this may be insufficient to meet the author's marketing objectives.
Therefore, authors and producers of copyrightable materials seek secure ways of distributing copyrightable materials in electronic form to purchasers of the materials, and allowing these bona fide purchasers convenient access to the purchased materials, while at the same time preventing subsequent unauthorized copying. Further, it would be advantageous for authorized digital materials to be portable from one computer to another for the authorized purchaser.